In the field of silver halide light-sensitive color photographic materials, color images prepared employing couplers requires neither color variation nor color fading when exposed to light over extended hours or stored at high temperature and humidity.
However, it has been known that these color images exhibit unsatisfactory fastness, mainly against ultraviolet rays or visible light, and when subjected to exposure of such actinic light, the colors of images easily vary and fade. In order to minimize these disadvantages, heretofore, methods have been proposed in that couplers are selectively employed which form images with improved fading resistance; UV absorbers are incorporated to protect dye images from ultraviolet rays or a group which improves light fastness is substituted to a coupler moiety.
However, for example, in order to result in satisfactory light fastness of a dye image employing a UV absorber, a relatively large amount of the UV absorber is required and when a large amount of the UV absorber is added, the dye image has been occasionally stained due to the tint of the UV absorber itself. Furthermore, in spite of incorporation of the UV absorber, fading of the dye image due to visible light is not prevented. The improvement in light fastness employing UV absorbers is limited.
In addition, a method has been known in which dye image fading inhibiting agents are employed which have a phenolic hydroxyl group or a group which forms a phenolic hydroxyl group upon hydrolysis, and for example, Japanese Patent Publication Nos. 48-31256, 48-31625, and 51-30462; Japanese Patent Publication Open to Public Inspection Nos. 49-134326 and 49-134327 proposes phenols and bisphenols; U.S. Pat. No. 3,069,262 discloses pyrogallol, gallic acid and esters thereof; U.S. Pat. Nos. 2,360,290 and 4,015,990 disclose .alpha.-tocopherols and acyl derivatives thereof; Japanese Patent Publication No. 52-27534, Japanese Patent Publication Open to Public Inspection No. 52-14751, and U.S. Pat. No. 2,735,765 describe hydroquinone derivatives; U.S. Pat. Nos. 3,432,300 and 3,574,627 describe 6-hydroxychromans; U.S. Pat. No. 3,573,050 disclose 5-hydroxychroman derivatives; Japanese Patent Publication No. 49-20977 describes 6,6'-dihydroxy-2,2'-spirobichromans. These compounds, however, exhibit to some extent functions as fading inhibition and hue change preventing agents, but do not exhibit a sufficient effect of these.
Furthermore, U.K. Patent No. 1,451,000 describes that the stability of a dye image for light is improved by employing azomethine light-quenching compounds which exhibit a more bathochromic absorption peak than that of the dye image. However, the azomethine light-quenching compounds are disadvantageous because of a large effect to the hue because they themselves are tinted.
Furthermore, Japanese Patent Publication Open to Public Inspection No. 50-87649 and Research Disclosure Item No. 15162 (1976) describe a method in which the stability of dyes for light is improved employing metal complexes. However, these complexes do not result in sufficient fading inhibiting effect and in addition to this, a sufficient amount cannot be incorporated so as to exhibit the fading inhibiting effect, because their solubility in organic solvents is not large enough. Furthermore, because these complexes are highly tinted, a large amount of their addition results in adverse effects to the hue and purity of a dye image formed through color development.
In the silver halide light-sensitive photographic materials provided for direct appreciation (hereinafter referred to as "light-sensitive material"), for example, color photographic paper, etc., a combination of a yellow coupler, a magenta coupler, and a cyan coupler as dye-forming agents to form dye images is generally employed. These couplers are required to form dyes which meet basic performance requirements such as color reproduction properties of a formed dye image, dye-forming efficiency, keeping stability of a formed dye image, etc. Particularly, in recent years, color reproduction faithful to the genuine color of a subject has been markedly demanded.
As cyan image-forming couplers, conventionally, phenol series or naphthol series couplers have been widely employed. On the other hand, the cyan dye image prepared employing these phenol series or naphthol series couplers exhibit no sharp cut at the short wavelength side and exhibit unwanted absorption in the green region, that is, non-uniform absorption, which has resulted in insufficient color reproduction. In order to overcome this problem, pyroloazole-type cyan couplers are proposed in Japanese Patent Publication Open to Public Inspection Nos. 5-313324, 5-313325, and 6-347960. However, it has been found that these pyroloazole-type cyan couplers -exhibit insufficient dye-forming efficiency and dye images obtained thereby exhibit insufficient light fastness.
On account of this, in color negative films, the unwanted absorption should be corrected employing masking agents, etc., and on the other hand, no correction means is available for color paper to degrade remarkably color reproduction.
In order to improve color reproduction, pyrazolotriazole-type cyan couplers are proposed in Japanese Patent Publication Open to Public Inspection Nos. 63-250649, 63-250650, 64-554, etc. However, all these couplers are substituted with an electron attractive group and a hydrogen bonding group so as to form a color developed dye having a satisfactory absorption wavelength. Thus, on the contrary to preferred color reproduction, the coupling activity has not been satisfactory.
Furthermore, recently, in light-sensitive color photographic materials, which are provided for direct appreciation, excellent keeping stability, especially excellent light fastness has been demanded. In order to improve the light fastness, the addition of various additives, specifically, image stabilizing agents, has been known. However, when the dye image stabilizing agents are employed, they cause problems such as a decrease in maximum density and also a decease in contrast.
The silver halide light-sensitive color photographic material is subjected to exposure and then to a color development process which forms a color image through the formation of dyes upon allowing to react a p-phenylenediamine series color developing agent with couplers. In this photographic method, color reproduction is carried out employing the subtractive color method and a color image composed of yellow, magenta, and cyan superimposed images is formed.
Representative cyan dye-forming couplers are phenols and naphthols. Of these, the naphthols are employed for negative films because the absorption of a resultant dye can be extended to a longer wavelength, and also because the rate of the coupling reaction is high.
In the past, naphthols substituted with a carbamoyl group in the 2-position have been employed. However, problems arise in which the cyan dye obtained by this type of cyan coupler readily undergoes reduction fading and when processed with an exhausted bleach solution, the density obtained by color development decreases. On the other hand, technology to overcome the above-mentioned problems employing 1-naphthols newly substituted with a substituent in the 5-position is described in Japanese Patent Publication Open to Public Inspection Nos. 60-237448, 61-153640, and 63-208042. Furthermore, Japanese Patent Publication Open to Public Inspection No. 8-95212 discloses naphthols substituted with an arylcarbamoyl group in the 2 position. The compounds described in the above-mentioned Publication exhibit to some extent improvements in the reduction fading of a cyan dye and decrease in density caused by processing which enmloys an exhausted bleach solution. However, improvements are found to be insufficient and the secondary absorption of these cyan dyes is not preferred. Accordingly, further improvements have been desired.